Members jjang1993 Posted May 10, 2016 Members Share Posted May 10, 2016 Deleted for privacy and safety reasons Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 10, 2016 Members Share Posted May 10, 2016 Sometimes its just a matter of tightening the speaker mount screws. Sometimes they vibrate loose and allow the speaker basket/frame to flex and you get the speaker cone to rub or the speaker to vibrate against the baffle. Tighten the screws that mount the speaker, evenly like you would a drum head so the tension on each is the same. Make them firm but don't overtighten. You can bend those stamped steel frames and warp the basket and cause the exact problem you're trying to get rid of. Other things to check, the Baffle or grill may be loose. I'm not sure about the build on those cabs, but some fender amps had the baffle screwed in. Make sure the screws are tight. Some vintage Fenders had a thin plywood baffle which were only secured on two sides, the idea being the entire baffle would vibrate like a drum head to produce warmer tones in a small combo. These floating baffles would commonly get loose and make for some odd vibrations. Be sure the screws which mount the head and hardware are tight too. Bass frequencies can cause anything that's loose to vibrate. If all of that is secure, then maybe the stock speaker by itself just isn't beefy enough. Most stock speakers, especially some of the newer Fender stock speakers provide the bare minimum durability for the head. Getting a better speaker can make a world of difference. It may also be you're just experiencing either guitar pickup microphonics or sympathetic feedback. A guitar pickup can feed back if its not potted with wax. Sympathetic feedback is caused by sound from the speaker hitting the guitar body. The vibrations cause the strings to vibrate on their own in a self sustaining feedback loop. These resonances are can be used to a guitarists advantage once he learns how to manipulate them. Musicians like Hendrix to Santana are masters are getting the sustain and harmonic to occur at will and use them to their advantage. The simple way of telling is its a Microphonic feedback is to dampen your guitar strings with your hand, then turn your amp up with allot of gain, then stick your guitar pickup in front of the speaker. If you get a high frequency squeal that sounds like microphone feeding back its your guitar pickups. You'll need to pot them to get rid of the microphonics. To determine is its Sympathetic vibration, get a long cord and move far away from the speaker. Sympathetic vibration changes as you change your guitar body angle to the speaker and change distances from the speaker. You can null the sound simply you changing the guitar angle 90 degrees to the speaker and increase it by putting the flat side of the body directly in front of the speaker while you're letting strings ring out. . It may be when you are playing through this amp you been sitting in front of it in the same position. Strap it up and walk around when you play. If you hear this resonance come and go as you move around, its absolutely normal for this to happen. Learn to use it to your advantage. Link to comment Share on other sites More sharing options...
Members gardo Posted May 10, 2016 Members Share Posted May 10, 2016 I think that JJ's are great tubes and Groove Tubes are pretty good so I wouldn't keep buying tubes. I had an issue with one of my amps that was caused by the spring reverb vibrating. Could the amp chassis be vibrating since the problem is gone when the chassis is removed ? Link to comment Share on other sites More sharing options...
Members thatsbunk Posted May 10, 2016 Members Share Posted May 10, 2016 Don't own this amp but from you description & diagnosis so far it seems you only notice the overtones when the chassis is in the same "box" as the speaker. Could something within the chassis be rattling or loose? I don't think it would be the speaker mount or baffle as you said the problem is gone when connecting your blues junior to the super champ speaker... Link to comment Share on other sites More sharing options...
Members Grant Harding Posted May 10, 2016 Members Share Posted May 10, 2016 Sure sounds like a cabinet or component vibrating, especially if it's certain notes that make it worse. I'd eliminate that before spending any money. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 10, 2016 Members Share Posted May 10, 2016 . . . maybe the stock speaker by itself just isn't beefy enough. Most stock speakers' date=' especially some of the newer Fender stock speakers provide the bare minimum durability for the head. Getting a better speaker can make a world of difference. . . .[/quote'] I seriously doubt the stock speaker can't handle 15 Watts. The stock unit is a "Fender® Special Design (P/N 0073858000)", probably a rebranded Eminence. You're right that a better speaker can make a world of difference but I doubt that's the solution in this case. If the amp didn't have new tubes I'd suspect microphonics. Link to comment Share on other sites More sharing options...
Members Grant Harding Posted May 11, 2016 Members Share Posted May 11, 2016 I also have an amp with a plastic logo that vibrates on certain notes. I put a bit of blue tack on it and the buzz is gone. Check for that too. Link to comment Share on other sites More sharing options...
Members jjang1993 Posted May 11, 2016 Author Members Share Posted May 11, 2016 Deleted for privacy and safety reasons Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 11, 2016 Members Share Posted May 11, 2016 Have you narrowed down to the sound as being a mechanical rattle/ hum or is at something electronic? You might want to try and get the amp raised up closer to ear level in the center of the room so you can walk around it 360 degrees when you play. You can often isolate where the noise is coming from more easily that way. Link to comment Share on other sites More sharing options...
Members mrbrown49 Posted May 11, 2016 Members Share Posted May 11, 2016 I had a similar issue on an amp a few years ago. On certain notes there was an over driven tone, even though the amp was set mainly clean. It turned out to be a defective speaker. The voice coil was rubbing on the frame or something like that. Link to comment Share on other sites More sharing options...
Members Karma1 Posted May 11, 2016 Members Share Posted May 11, 2016 That sounds like a similar issue I read about a few years ago that was common in Fender Pro Jr. amps. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 12, 2016 Members Share Posted May 12, 2016 That's why I mentioned for him to see if all the speaker screws have even tightness. More then once I've had to remove the speaker and flex its frame to get rid of the rubbing. Those Stamped steel frames are pretty flexible. Other times the paper cone shifts when the glue is drying. I can sometimes move the coil by hand giving some side pressure to find which side the piston is rubbing on the magnet, then flex the cone so it doesn't rub any more. Some times the dust cap doesn't have enough glue and just flaps in the wind. A little speaker glue to tack it back down fixes it. I've also had instances where a piece of metal shaving or dirt that gets in the magnet groove. There's really no way to get at it besides a re-cone and if the speaker cost less then $100 its cheaper to buy another. . These aren't things I'd advise an amateur to try but its the only things that can be tried besides a replacement. Personally I'd just get a different speaker in there. You can buy a 10" Eminence or Celestion for that amp for under $50 that has a higher SPL and make that amp really crank. Something like a Jensen Mod is about $35 new and would sound about the same. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 12, 2016 Members Share Posted May 12, 2016 Its common to allot of small amps. I have a 15w Marshall amp that has a Park speaker in there which is a low grade Celestion copy. The speaker was tight when new. I used it for some jams playing full blast and its since become flabby sounding. I crank up over half way now and its fart city. I'd replace it with something better but finding a good 8" speaker is slim pickins. Link to comment Share on other sites More sharing options...
Members Karma1 Posted May 12, 2016 Members Share Posted May 12, 2016 I actually have a Super Champ XD that I bought when they first came out. I've never had any problems with it, although I don't play very loud with it. After a while I did replace the stock speaker in it with a Jensen Neo just because I had one available and I liked the sound of it. Link to comment Share on other sites More sharing options...
Members jjang1993 Posted May 13, 2016 Author Members Share Posted May 13, 2016 Deleted for privacy and safety reasons Link to comment Share on other sites More sharing options...
Members mrbrown49 Posted May 13, 2016 Members Share Posted May 13, 2016 I'm assuming the tube sockets are mounted on the PCB. Make sure that is secured tightly. Very possibly it could be a microphonic issue with the tubes. If the boards loose it can vibrate. Careful poking around in there though, the cap can hold quite a charge. Lethal shocks can happen if your body completes the path to ground. Link to comment Share on other sites More sharing options...
Members jjang1993 Posted May 13, 2016 Author Members Share Posted May 13, 2016 I'll keep trying to track down where exactly the noise is coming from. Does anyone have any suggestions as to where I should put some weatherstripping foam? Link to comment Share on other sites More sharing options...
Members mrbrown49 Posted May 13, 2016 Members Share Posted May 13, 2016 The only place I've seen that used effectively is between the back panel and chassis. I'd take the back panel off first though and if the noise is still there it won't do you any good. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 13, 2016 Members Share Posted May 13, 2016 I'll keep trying to track down where exactly the noise is coming from. Does anyone have any suggestions as to where I should put some weatherstripping foam? Since the "feedback" isn't there when you power the Super Champ with the Blues Jr. and the noise changed with different tubes, that suggests microphonics. I don't know enough about how that amp is put together but it seems like you need to isolate the amp part from vibration. Link to comment Share on other sites More sharing options...
Members jjang1993 Posted May 14, 2016 Author Members Share Posted May 14, 2016 Deleted for privacy and safety reasons Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 15, 2016 Members Share Posted May 15, 2016 ^ Okay, yeah. The chassis of the amp is transmitting vibration to the tubes. You need to create some sort of shock mounting. Is there room for maybe a rubber washer between the screw and the chassis? Link to comment Share on other sites More sharing options...
Members mrbrown49 Posted May 16, 2016 Members Share Posted May 16, 2016 Glad to hear you are zeroing in on your problem. Do you think it's a vibration being picked up by the tubes, all tubes have some level of microphonics, or is it just the mechanical buzzing of the sheet metal against the cabinet? Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 16, 2016 Members Share Posted May 16, 2016 Glad to hear you are zeroing in on your problem. Do you think it's a vibration being picked up by the tubes' date=' all tubes have some level of microphonics, or is it just the mechanical buzzing of the sheet metal against the cabinet?[/quote'] I think if it were sheet metal vibrating the OP would have the same issue playing another amp through the Super Champ speaker. Since he doesn't I'm leaning toward vibration picked up by the tubes. Link to comment Share on other sites More sharing options...
Members mrbrown49 Posted May 16, 2016 Members Share Posted May 16, 2016 I think if it were sheet metal vibrating the OP would have the same issue playing another amp through the Super Champ speaker. Since he doesn't I'm leaning toward vibration picked up by the tubes. Good point. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted May 16, 2016 Members Share Posted May 16, 2016 Thanks. I'd originally ruled out microphonics because the OP had installed new tubes. It took three days of reading posts before I considered it again. I should have listened to my gut. Link to comment Share on other sites More sharing options...
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